code: def test_lowpass(self):
      self.assertEqual(testmod(lowpass).failed, 0)
  
file_path: julius/tests/test_doc.py
imports: from doctest import testmod
  import unittest
  from julius import resample, fftconv, lowpass, bands, utils
label_desc: Use image node_id 3 for calling the DocStringTest obj's underlying member method code with example usage: obj.test_lowpass() without return types